Centralizer for drill steels



Sept; 17, 1'940. G. H. `FuEJ-u'ER 2,214,789

CIEHTALIZEB FOR DRILL STEELS w Filed nay 21, 193e 22 "o" f l f HIS ATTORNEY Patented Sept. 17, 1940 CENTRALIZER FOR DRILL STEELS George H. Fuehrer, Phillipsburg, N, J., assignor to Ingersoll-Rand Company, Jersey City, N J.,

a corporation o! New Jersey Application Mayer 193s, serial Nazoaisz 4 Claims.

This invention relates to rock drills, and more particularly to a centralizer for a drill steel actuated by a rock 'drill of the reciprocatory type.

In many drilling operations it is difcult to maintain the cutting end of a drill steel in coaxial alignment with the rock drill during the starting of a drill hole. This is more particularly true when the rock drill lies in an inclined or horizontal position. Under such conditions the cutting Vl0 end of a rapidly rotating drill steel whips or describes a gyratory movement which makes it difcult to start the drill hole correctly.

This erratic action of the drill steel is partly due to its inherent exibility and in part to the natural clearances between the drill steel and the chuck mechanism of the rock drill into which it extends. In drilling mechanisms in which chuck parts form the only support forthe drill steel, and particularly when these chuck parts become worn, the drill steel declines from the desired course of the drill hole and thereby speedily develops a condition in which the action of the rotation mechanism of the rock drill is hampered seriously.

These unfavorable conditions often continue undetected until the drill hole has been drilled to a considerable depth. If then the position of the rock drill is not changed to coincide with the course of the hole, as drilled, the drill steel will bind in the work, thereby causing excessive wear on the gaging surfaces of the cutting bit. Ob- 'viously, this will lower the drilling eiliclency of the apparatus and add materially to the cost of maintenance sin-ce it necessitates the frequent '35 reconditioning of the drill steel.

It is accordingly an object of the present invention to stabilize the overhanging portion of the drill steel and thereby maintain the cutting bit in axial alignment with the rock drill actuating the drill steel.

Another object is to enablethe centralizer to be conveniently movedinto the guiding and nonguiding positions.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this specifica--v tion and in which similar reference numerals refer to similar parts:

Figure l is a longitudinal side elevation of rock drilling apparatus equipped with a centralizer constructed in accordance with the practice of the invention,

Figure 2 is an end elevation of the centralizer and the rock drill taken through Figure 1 on the line 2-.2 and showing the guide elements of the centralizer in non-guiding position, Figure 3 is an elevation, partlyin section, taken Athrough Figure 1 on the line 3-3,

Figure 4 is a transverse view taken through 5 Figure 3 on the line 4-4 looking in the direction indicated by the arrows, and

Figure 5 is a similar view taken through Figure 2 on the line 5-5.

Referring more particularly to the drawing, 20 10 and 2| designate the front ends of a rock drill and a shell, respectively, and 22 a drill steel, the shank of which may extend into the front end of the rock drill 20 to receive the blows of a hammer piston (not shown). 'I'he opposite or free end of u the drill steel 22 constitutes the cutting bit 23 for drilling holes into rock 24.

The rock "drill 20 and the shell 2| are of the type that are usually provided with interlocking guiding elements (not shown) to enable the 2U vrock drill to be advanced toward. the work in accordance with the penetration of the drill steel 22` thereinto.

The centralizer, constructed in accordance with the practice of the invention and designated in 2l its entirety by 25, is attached to the front end of the shell 2|. It comprises a support 26 having a flange 21 which seats against and is clamped to the front end of the she1l'2l by bolts 28. On the opposite end of the support 26 are a pair of 3( trunnions y29 which serve as pivots for guide arms 30 serving to maintain the drill steel 22 in axial alignment with the rock drill 20.

The trunnions 29 are inclined with respect to the longitudinal axis 0f the support 26 and ar- 3i ranged angularly with respect to each other. They may, as shown, be integral parts of the support or formed as separate members and suitably attached to the support.'

The guide arms 30 are seated loosely upon the 4| trunnions 29 whereon they rotate, and to this end are provided with cup-shaped hubs 3| having sockets 32 to receive the trunnions 29. Preferably, the trunnions 29 are of somewhat less length than the depth of the Asockets 32 and seat- 4l ing surfaces 33 are provided at the bases of the trunnions for the hubs 3|.

As a preferred form of construction the guide arms 30 are located at the outer or closed ends of the hub 3|. 'I'hese guide arms may be slightly 5l bowed, as illustrated, and terminate in heads 34 having partly cylindrical recesses 35 in their opposed surfaces to receive the drill steel 22. Suiiicient clearance is provided between the recesses 35 and the body portion of the drill steel 5| to allow the latter to rotate freely within the recesses.

Suitable means are provided to prevent endwi'se movement of the hubs 3| with respect to the trunnions 29 and also to maintain the guide arms in the various positions which they will occupy in practice. To this end the portions of the hub 3| adjacent the seating surfaces 33 are provided with flanges 36 having on their upper end s seating surfaces, three in the present instance, designated 31, 33 and 39 which are inclined with respect to the axes of the hub 3|.

'I'he degree of inclination oi the seatingsurfaces is the same as that of the trunnions with respect to the axis of the support. VThus, when the guide arms occupy a Aposition in which they engage the drill steel the seating surface 31 will lie in a horizontal. plane and provide a-seat for.

' a clamping member or plate 40 whereby the guide arms are retained on the trunnions. 5

Likewise, the, surfaces, either 33. or 33, depending upon whether 'a given guide arm occupies the right or the left handA trun'nion,' will.lie in thehorizontal plane in the non-guiding positions of.' the guide arms shown-'in Figure 2 toprovide a,

seat for the plate 40'.

In this connecti'n it may be pointed voutgtliat only one seating s two surfaces are provided in order to enable the guide arms to be interchanged and also t9,avoid the waste of'time that is often occasioned inv determining whether the guide arms are correctlyl assembled on the support. y

For a like reason thejplate 4,0 is provided -at` to avoid vibratory movement of 'the guide armsA with respect to the trunnionsfand, therefore, wear on the cooperating surfaces of these elements.

.The element serving to press the plate 46 against the seating surfaces on the anges 36 consists, in the present instance, of a spring 42 inserted in a recess in the lower surface of the support 26. The spring 42 encircles a bolt 43 having a head 44 which serves as a seat for an end of the spring. The bolt extends through the support 26 and the plate 40 and has a nutl 45 threaded on its upper end for adjusting `the spring 42. Preferably, a round faced washer 46 is interposed between the nut 45 and the plate 40 and seats into a concave recess 41 in the plate 40 to enable the plate 40 to adjust itself readily with respe'ct to the seating surfaces on the guide face 38 or 39 is utilfzed'ini the non-guiding pos tions of the guide arms but,

In the operation of the device, whenever it is desired to start a new drill'hole, the armsv 26 are rocked to the guidingpositions in which the drill steel 22 lies in the recesses 35. In this position of the guide arms the clamping plate 40 will seat upon the surfaces 31 and will hold the guide arms immovable.

The arms remain in the'guiding position during the ensuing drilling operation and when the rock drill advances into contact with the portions of the arms encircling the drill steel said arms will be rocked out of the guiding position into a non-'guiding position in which the surface 38 of one arm and asurface 33 of the other arm will lie beneath the plate 40. Thedrill may thereafter continue operation and its advancing movement until the` working implement has penetrated the .,rockto the limit of its extent. After the rock theguia .j I claim:

drillZJll-'has'been-retracted 'on the shell 2| and anewadrill. steel of grater length'placed therein rms25- are again, rocked to the guiding position shown in. Figures 1 and 3 to support thedrill steel.

' 1. A centralizer the pivots, and means on the guide arms eng'agi ing the spring-pressed member for holding the guide arms in guiding' and non-'guiding positions.

2v. lA centralizer forydrill steels, comprising a support, a pair of guide arms, pivots on the supports for the'guidearms arranged angularly with respectvto each other,'a plurality of seating surfaces on; the guide arms,and a spring-pressed member on the support, toengage the seating angularly with respect to each other, anges on the hubs each having a plurality of seating surfaces, and a spring-pressed plate on the support to engage the seating surfaces for retaining .the guide arms on the pivots and holding the guide arms in guiding and non-guiding positions.

4. A centralizer for drill steels, comprising a support, a pair of guide arms, pivots on the support for the guide arms, hubs on the guide arms having sockets to receive the pivots, a plurality of seating surfaces on the hubs inclined with respect to the axes of the hubs and with respect to each other, and spring-pressed means on the support to engage the seating surfaces for retaining the guide arms on the pivots and for holding the guide arms in guiding and nongulding positions.

GEORGE H. FUEI-IRER.

for drill steels, comprising a, supPOrt, a pair' ofguide arms, pivots on the supy' i -1 Vportior the guide ar'ms arranged angularly with frespectto eachother, a spring-pressed member .'on the support'for retaining the guide arms on i?! if 

